On the structural and optical properties investigation of annealed Zn nanorods in the oxygen flux

Zn nano rods were produced on glass substrates using oblique angle deposition method at different deposition angles. For oxidation, the samples were placed in a furnace under oxygen flux. AFM and FESEM images were used to morphology analysis of the structures. The results showed that with increasing the angle of deposition, the grain size decreases and the porosity of the structures increases. XRD pattern and XPS depth profile analysis were used to crystallography and oxide thickness investigations, respectively. The XRD results confirmed oxide phase formation, and the XPS results analyzed the oxide layer thickness. The result showed that as the deposition angle of the nanorods increases, the thickness of the oxide layer increases. The reason for the increase in the thickness of the oxide layer with increasing deposition angle was investigated and attributed to the increase in the porosity of the thin films. The optical spectra of the structures for p polarized light at 10° incident light angle were obtained using single beam spectrophotometer in the 300 nm to 1000 nm wavelengths. The results showed that the formed structures although annealed in oxygen flux, tend to behave like metal. To calculate the optical constant of the structures, the reverse homogenization theory was used and the void fraction and complex refractive index of the structures were obtained. Finally, by calculating permittivity and optical conductivity of the structures, their changes with the deposition angle were investigated.     

Control of all‐conjugated block copolymer crystallization via thermal and solvent annealing

Control of the crystallization of conjugated polymers is of critical importance to the performance of organic electronics, such as organic photovoltaic devices, due to the effect on charge separation and transport, particularly for all‐polymer devices. The block copolymer poly(3‐dodecylthiophene)‐block‐poly(9,9‐dioctylfluorene) (P3DDT‐b‐PF), which has matched crystallization temperatures for each block, is used to study the effects of processing history on resulting crystallization. For longer annealing times and rapid quenching to room temperature, P3DDT crystals are preferred whereas for shorter annealing times and slower quenching, PF crystals are preferred. Both crystal forms are evidenced for long annealing time and slow quenching. Additionally, for room temperature annealing in the presence of a chloroform vapor, PF crystals are found in the PF β phase with the predominant crystal peak oriented perpendicular to the thermally annealed case. These results will provide guidance for optimizing annealing strategies for future donor/acceptor block copolymer photovoltaic devices. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 900–906     

Wholly-rigid rod–rod amphiphiles: synthesis,crystal structures,and self-assembling behavior in water

A series of fully rigid rod–rod type amphiphilic molecules have been constructed by using 4,4′-bipyridin-1-ium or 4,4′-bipyridin-1,1′-diium (viologen) as a hydrophilic segment and phenyl, biphenyl or para-tert-phenyl as a hydrophobic unit. The crystal structures of four of the molecules have been elucidated. TEM, SEM, AFM, and DLS experiments revealed that these stiff amphiphiles could self-assemble into diverse architectures, including spherical micelles, ultra-long straight nanofibers (>1 mm), and nanotubes in water, which depend on the hydrophilic/hydrophobic fraction ratios of the molecules.     

有杆抽油系统动态特性的计算机仿真

本文建立了有杆抽油系统动态特性仿真的综合数学模型．即应用数值积分法建立转子运动规律的仿真模型和应用差分法建立抽油杆柱纵向振动的仿真模型。本文提出了一种叠代方法较好地解决了两子系统之间相互耦合的问题，给出了一种便于应用的井下边界条件的仿真方法。     

Assessment of transmission of the shear stress in potted anchors for composite rods 1. Sleeve of constant thickness

The key problem facing the application of fiber-reinforced polymer (FRP) stay cables and tendons is the anchorage. Potted (bond-type) anchors have been used more extensively than anchors of any other type. The main aim in the design of anchors is to minimize the peak shear stress at the FRP rod-pottant interface. To this end, parametric analyses of the stress state in the anchors are carried out. Since parametric studies can not be easily performed by the finite-element method, an analytical model of the anchor is proposed. The model involves significant simplifying assumptions and allows one to obtain a relatively simple analytical solution for shear-stress distributions at the FRP rod-pottant interface. The use of this solution at various boundary conditions and various geometrical and mechanical parameters of anchor components enables one to search for and evaluate, at least qualitatively, different methods for decreasing the peak interfacial shear stress in the anchor. In this part of the investigation, an anchor consisting of a sleeve of constant thickness is considered. Russian tanslation published in Mekhanika Kompozitnykh Materialov, Vol. 45, No. 3, pp. 321-346, May-June, 2009.     

Modelling of recrystallization behavior and austenite grain size evolution during the hot rolling of GCr15 rod

In this paper, four 3-D finite element models are developed to simulate the whole rod rolling process of GCr15 steel. The distribution and evolution of different field-variables, such as effective strain, effective strain rate and temperature, are obtained. Based on the simulated results and the microstructure evolution models of the steel, the paper designs a FORTRAN program to predict the evolution of recrystallization behavior and austenite grain size in rolled piece during the rolling. The surface temperatures of rolled piece calculated by FEM agree well with measured values. Comparison between calculated values and measured ones of grain size shows the validity of the program.     

Silicone rod and silicone tube sorptive extraction

This review focuses on the applications of silicone in the form of tubes or rods for sorptive extraction of organic compounds as sample preparation method in combination with various chromatographic techniques. Silicone rods (SRs) and silicone tubes (STs) have the advantage of being inexpensive, flexible and robust. SRs and STs with different sizes and volumes of silicone (8–635 μL) have so far been applied for the extraction/preconcentration of a large variety of organic micropollutants from different matrices. The theoretical principle of SR and ST extraction in comparison with similar microextraction techniques is presented as well as a summary of the published applications of SR and ST extraction in combination with gas chromatography (GC) or liquid chromatography (LC). Furthermore, the use of SRs and STs for time-integrated (passive) sampling is reported.     

振动杆有限差分模型的一类特征值反问题

1引言杆是重要的工程构件之一,具有分布质量的杆的纵向振动由下面的偏微分方程描述:     

Synthesis and physical properties of N-substituted polyimides based on imidazole

AB-type monomers based on imidazole for the preparation of polyimides were synthesized by carrying out a substitution at the 1-position of 2-amino-4,5-dicyanoimidazole, followed by hydrolysis. Thus, pendant groups such as hexyl and 2,4-dinitrophenyl as an aliphatic long chain and an electron-withdrawing group, respectively, were introduced at the 1-position of the imidazole monomer. A solid-state polymerization was employed to prepare the poly(imidazoleimide)s in the form of a film from poly(imidazoleamic acid chloride)s by heating up to 180–200°C. The carbonyl stretching peaks of the imide ring appear at 1808 (sym) cm^?1 and 1756 (antisym) cm^?1. The effects of monomer structure on reactivity and the degree of imidization were investigated by comparing the viscosity of the resultant polymers and intensity of carbonyl peak at 1808 cm^?1. The difference in the hydrolysis rate between polyimides having short or long aliphatic pendant groups at the 1-position was observed using FT-IR. The inherent viscosity of the N-hexyl polyimide was 1.26 dL/g in N-methyl pyrrolidinone (NMP) and 0.22 dL/g in the case of N-2,4-dinitrophenyl poly(amic acid) in methanesulfonic acid at 30°C. The structural, physical, and material properties of the polyimides were characterized by infrared, nuclear magnetic resonance, luminescence, viscosimetric methods, differential scanning calorimetry, thermogravimetric analysis, optical microscopy, and wide angle x-ray scattering. Solution properties were also investigated by monitoring the viscosity as a function of time at 30°C. Luminescence spectroscopy of the poly(1-methyl imidazole imide) and poly(1-methyl imidazoleamic acid) films shows an emission band centered at 535 and 505 nm, respectively. Thermal properties are described comparing the weight loss and decomposition temperature as a function of the polymer structure and the degree of imidization. © 1993 John Wiley & Sons, Inc.     

原位聚合法分子复合材料的研究进展

论述了原位复合材料的发展及最新研究动态，重点介绍了近十几年来国内外在原位聚合分子复合材料的制备、结构与性能、增强机理等方面的研究状况、预示了原位分子复合材料的开发前景。